Greetings, Suresh --
1. You can open a PDF using the WebImageViewer.OpenUrl(). Before you do this, though, you will want to add the PdfDecoder to the list of RegisteredDecoders:
Atalasoft.Imaging.Codec.RegisteredDecoders.Decoders.Add(new Atalasoft.Imaging.Codec.Pdf.PdfDecoder());
2. Currently, PDF Annotations are not supported in the web, but that functionality is on our feature improvement list. I do not have an estimated date of when we will address them, but it will hopefully be soon.
3. With PdfEncoder.Save() will let you save a single image or a collection of images as a pdf.
Elaine McNealy
Developer Support Supervisor
Atalasoft, Inc.